Field of the Invention
The present invention relates to information processing of measuring the position and orientation of an object.
Description of the Related Art
Along with development of robot technology, robots are increasingly performing complex tasks such as assembly of industrial products, which have been conventionally done by humans. A robot grips parts using an end effector such as a hand, and assembles them. In this assembling operation, it is necessary to measure the relative position and orientation between the robot (hand) and a part to be gripped.
As a position and orientation measurement method, there is provided model fitting in which the three-dimensional shape model of an object is fitted to features detected from a two-dimensional image captured by a camera or range data measured by a range sensor.
In model fitting for a two-dimensional image, a position and orientation is measured so that a projected image obtained by projecting a three-dimensional shape model onto an image based on the position and orientation of an object fits detected features. In model fitting for range data, respective points in a range image expressing range data are converted into a group of three-dimensional points each having three-dimensional coordinates, and a position and orientation is measured so that a three-dimensional shape model fits the three-dimensional point group in a three-dimensional space.
It is possible to measure the position and orientation of an object with higher accuracy using both measurement information obtained from a two-dimensional image and measurement information obtained from range data.
Japanese Patent Laid-Open No. 2012-021958 (literature 1) describes a method of selecting, in accordance with the shape of an object to be measured (to be referred to as a “target object” hereinafter), one of a position and orientation measurement method using measurement information obtained from a two-dimensional image, a position and orientation measurement method using measurement information obtained from range data, and a method using both the position and orientation measurement methods, and measuring the position and orientation of the target object by the selected method. Since the method described in literature 1 performs measurement by a method optimum for the shape of a target object, measurement can be performed with high accuracy at high speed.
However, when a capturing device captures a target object while moving, the influence of a motion blur degrades the estimation accuracy of the position and orientation. It is difficult to estimate the influence of a motion blur based on only shape information. In the method of measuring the position and orientation by selecting observation information from the shape information, which is described in literature 1, therefore, when a capturing device captures a target object while moving, it is impossible to measure the position and orientation of the target object with high accuracy.